1. Utah Cost of Service and Rate Design Task Force Seasonality in Costs and Loads Maurice Brubaker June 15, 2005 Salt Lake City, Utah

2. PacifiCorp-Utah Comparison of Monthly Peaks for Years 1994 and 2006 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month Megawatts 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Percentage Change 1994 Percentage Change 2006

3. 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 0% 5% 10% 15% 20% 25% 30% PacifiCorp Comparison of Monthly Peaks for Years 1994 and 2006 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month 1994 Percentage Change 2006 Megawatts Percentage Change

4. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 1337673100913451681201723532689302533613697403343694705504153775713604963856721705773937729806584018737 Hourly Load Data - Utah PacifiCorp Hour MW

5. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulAugSepOctNovDecJanFebMar-06 Month MW Total Total Residential Schedule 6 PacifiCorp-Utah Contribution of Major Classes to Coincident Peak Schedule 8 Schedule 9 Schedule 23

6. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Hour 116824487296120144 PacifiCorp-Utah Hourly Load Data for Total Utah and Large Industrial Customers Maximum Winter Week Total Utah Large Industrial Customers MW % Increase = 48%

7. 116824487296120144 MW PacifiCorp-Utah Hourly Load Data for Total Utah and Large Industrial Customers Maximum Summer Week Hour Total Utah Large Industrial Customers % Increase = 72%

8. $20 $25 $30 $35 $40 $45 $50 $55 $60 $65 $70 ($/MWh) Jan-04FebMarAprMayJunJulAugSepOctNovDec Peak Off-Peak COB Average Monthly On-Peak Prices 2004

9. $20 $25 $30 $35 $40 $45 $50 $55 $60 $65 $70 Jan-04FebMarAprMayJunJulAugSepOctNovDec ($/MWh) Peak Off-Peak Palo Verde Average Monthly On-Peak Prices 2004

10. $20 $30 $40 $50 $60 $70 $80 1/2/2004 1/16/20041/30/20042/13/20042/27/20043/12/20043/26/2004 4/9/2004 4/23/2004 5/7/2004 5/21/2004 6/4/2004 6/18/2004 7/2/2004 7/16/20047/30/20048/13/20048/27/20049/10/20049/24/200410/8/2004 10/22/2004 11/5/2004 11/19/2004 12/3/2004 12/17/200412/31/2004 COB Day Ahead On-Peak Prices 2004 ($/MWh)

11. 1/2/2004 1/16/20041/30/20042/13/20042/27/20043/12/20043/26/2004 4/9/2004 4/23/2004 5/7/2004 5/21/2004 6/4/2004 6/18/2004 7/2/2004 7/16/20047/30/20048/13/20048/27/20049/10/20049/24/200410/8/2004 10/22/2004 11/5/2004 11/19/2004 12/3/2004 12/17/200412/31/2004 $20 $30 $40 $50 $60 $70 $80 ($/MWh) Palo Verde Day Ahead On-Peak Prices 2004

12. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulAugSepOctNovDecJanFebMar-06 Month MW Total Total Residential Schedule 6 Schedule 8 Schedule 9 Schedule 23 PacifiCorp-Utah Allocations Based on Peaks (Vertical Slices) ?

13. Resource Portfolio  Base Load Coal  Combined Cycle – Gas Fired  Peaking Units – Gas Fired  24 x 7 x 52 Purchases  Seasonal On-Peak Purchases  Seasonal Off-Peak Purchases  Hourly Purchases PacifiCorp-Utah

14. Block Purchases Day 1 Load Midnight 6 AMNoon10 PM 6 x 16 Purchase Surplus

15. PacifiCorp-Utah Block Purchases Day 2 Load Midnight 6 AMNoon10 PM 6 x 16 Purchase Surplus

16. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulSepOctNovDecJanFebMar-06 Month MW PacifiCorp-Utah Horizontal Analysis - Industrial Total Industrial Aug Base

17. 0 400 800 1,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulSepOctNovDecJanFebMar-06 Month MW Horizontal Analysis – Peaking Classes PacifiCorp-Utah Base Intermediate Peaking Super Peak Total Estimate Aug